Plant biotechnology journal 2016
Aldo-keto reductase enzymes detoxify glyphosate and improve herbicide resistance in plants.
In recent years, concerns about the use of glyphosate-resistant (GR) crops have increased because of glyphosate residual levels in plants and development of herbicide-resistant weeds. In spite of identifying glyphosate detoxifying genes from microorganisms, the plant mechanism to detoxify glyphosate has not been studied. We characterized an Aldo-keto reductase gene from Pseudomonas (PsAKR1) and rice (OsAKR1a>) an>d showed, by docking studies, both PsAKR1 and OsAKR1 can efficiently bind to glyphosate. Silencing AKR1 homologs in rice and Nicotiana benthamiana or mutation of AKR1 in yeast and Arabidopsis showed increased sensitivity to glyphosate. External application of AKR proteins rescued glyphosate-mediated cucumber seedlings growth inhibition. Regeneration of tobacco transgenic lines expressing PsAKR1 or OsAKRI on glyphosate suggests that AKR can be used as selectable marker to develop transgenic crops. PsAKR1 or OsAKRI expressing tobacco and rice transgenic plants showed improved tolerance to glyphosate with reduced accumulation of shikimic acid without affecting the normal photosynthetic rates. These results suggested that AKR1 when overexpressed detoxifies glyphosate in planta. This article is protected by copyright. All rights reserved.